A capacitive MEMS pressure sensor is a sensor that characterizes a value of a pressure acted to a pressure-sensitive layer by using a capacitance between the pressure-sensitive layer, which acts as an upper electrode, and a lower electrode. A conventional capacitive MEMS pressure sensor typically uses a single capacitor for pressure detection. As shown in FIG. 1, the conventional capacitive MEMS pressure sensor comprises a substrate 1′, an insulating layer 2′ formed on the substrate 1′, a lower electrode 3′ formed on the insulating layer 2′, and a pressure-sensitive film supported above the lower electrode 3′ via a supporting part 7′, wherein the lower electrode 3′ is electrically connected to a lower electrode bonding pad 5′; and the pressure-sensitive film, which acts as the upper electrode 4′, is electrically connected to an upper electrode bonding pad 6′. A pressure detection principle by using this capacitive MEMS pressure sensor is that the upper electrode 4′ deforms, correspondingly when being subjected to external air pressure, and then a capacitance of a parallel plate capacitor formed by the upper electrode 4′ and the lower electrode 3′ is changed accordingly, so that an output signal of the pressure sensor can be collected via an interface circuit to acquire a corresponding air pressure value, thereby realizing detection of the external air pressure. However, the capacitive MEMS pressure sensor is likely to be subject to common-mode interference such as electromagnetic interference, as it uses the single capacitor for external air pressure detection, resulting in instability and resolution reduction of the output signal of the pressure sensor. Consequently, the performance of a chip is reduced.
Therefore, there is a demand in the art that a new solution to address at least one of the problems in the prior art.